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. 2017 Jun 23;12(6):e0180029. doi: 10.1371/journal.pone.0180029

Fig 4. Ventricular effective refractory period (VERP) in WT and CVB3+ whole hearts.

Fig 4

(A) Recording of S1S2 electrical stimulation protocol in a Langendorff-perfused WT whole heart. ↓ = S1 electrical stimulus artefact. S1 cycle length was 120 ms (ms = milliseconds). Δ = S2 extra-stimulus for determination of VERP. In this example, S2 had a coupling interval of 46 ms that caused a subsequent ventricular depolarization. # = first intrinsic ventricular action potential. mV = millivolt, s = second. (B) Recording of S1S2 electrical stimulation protocol in a Langendorff-perfused CVB3+ whole heart. S2 extra-stimulus (Δ) coupling interval was also 46 ms that did not cause a subsequent ventricular depolarization, indicating ventricular refractoriness (VERP). (C) VERP in Langendorff-perfused WT and CVB3+ whole hearts. WT n = 5; CVB3+ n = 7; *p = 0.018. n = number of Langendorff-perfused hearts.